Improved method of grafting is:

Consider the following four statements $(a-d)$ regarding the successful cultivation of chickpea in an area where bacterial blight is common:
$(a)$ Spraying of Bordeaux mixture.
$(b)$ Control of the disease vector.
$(c)$ Use of disease-free seeds.
$(d)$ Use of disease-resistant varieties.
Which of the above are the most effective strategies for managing this disease?

In mutation breeding,mutations are induced by using radiation like

The $....X....$ variety of Brassica is resistant to $.....Y.....$ disease.

Triticale,the first man-made cereal crop,has been obtained by crossing wheat with

Semi-dwarf wheat was developed by